Neurodegenerative diseases such as Alzheimer's Disease (AD) and Multiple Sclerosis (MS) are exacerbated as a result of damaging neuroinflammation. A common theme observed with these neurodegenerative diseases is the activation of normally quiescent microglia to become potent antigen presenting ceils. Once activated, microglia elaborate a variety of cytokines, chemokines and neurotoxins that contribute to neuroinflammation. One of the mechanisms to activate microglia is the expression of CD40, a member of the TNF receptor superfamily. Interaction between CD40 and its ligand, CD154, is critical for a productive immune response. Activation of microglia also results in secretion of many chemokines, including monocyte chemo attractant protein (MCP-1) that causes the recruitment of new microglia J monocytes to the site of lesions in MS and senile plaques in AD. Ultimately, increased CD40 expression coupled with secretion of MCP-1 results in exacerbation of neuroinflammation. The development of drugs targeted to specifically inhibit or down modulate the production of CD40 and MCP-1 would have great utility in reducing neuroinflammation in the CNS. The goal of the experiments in this proposal is to develop drug targets specific for CD40 and MCP-1. These targets will be used to develop assays to identify drugs that can be utilized to specifically inhibit the expression of CD40 and MCP-1. To accomplish this goal, we will focus on the design and development of drugs targeted to specifically hind to mRNAs of MCP-1 and CD40 as a means to inhibit or down modulate expression. In this regard, small molecule agents that target RNA, notably the aminoglycoside antibiotics, are now actively being pursued as RNA targeted therapeutics to inhibit expression of specific proteins. The following Specific Aims are proposed: Specific Aim 1: To develop ligands that target MCP-1 and CD40 mRNAs. Specific Aim 2: To establish that the ligands inhibit expression of MCP-I and CD40 proteins. Once we have established and characterized the RNA targets in the mRNAs of MCP-1 and CD40, we will use this information to establish a high throughput screening assay for drugs that will specifically bind to these RNAs; for these studies, we will collaborate with the centralized high throughput screening facility that will be developed at NINDS. The best candidates can be screened for their capacity to down modulate MCP-1 and CD40 expression in in vitro glial cell culture systems.